Instrumentation

1. Create a Push button

2. Connect a Counter series to PB

3. Create a compare button

4. Initialize 1 at one end

5. Counter output in another

6. Connect the Coil which has to be energized

7. Initialize 2 at one end

8. Counter output in another

9. Connect the Coil which has to be reenergized.

Control valve can not be without positioner. The purpose of the positioner is to control the control valve stroke so as to keep the valve in desired position. The positioner receives signal from the controller, and send the boosted signal to the actuator to reach the desired position as and when the valve reaches the desired position the positioner cuts the boosted signal to the actuator and keeps the position.

Remote mount with MTA means MTA connector for mounting remote connection.

MTA is the Connector used for connection. Generally we called it MTA Connector.

There are many types of MTA connector such as MTA 100connectors, Mta 156 connectors etc...

Generally in a transistor some amount of voltage is required for turning it on. This voltage is the cut in voltage. Up to this voltage the exists a nonlinearity in its characteristics. Beyond this cut in voltage the char. of transistor is linear. This nonlinear region lays between 0-4ma, beyond 4ma it linear. This is why 4-20 ma range is used.

Instrumentation can be used to measure certain field parameters (physical values):

These measured values include:

* pressure, either differential or static

* flow

* temperature - Temperature_measurement

* level - Level Measurement

* density

* viscosity

* radiation

* current

* voltage

* inductance

* capacitance

* frequency

* resistivity

* conductivity

* chemical composition

* chemical properties

* various physical properties

In addition to measuring field parameters, instrumentation is also responsible for providing the ability to modify some field parameters.

Some examples include:

Device Field Parameter(s)

Valve Flow, Pressure

Relay Voltage, Current

Solenoid Physical Location, Level

Circuit breaker Voltage, Current

Instrumentation engineering is the engineering specialization focused on the principle and operation of measuring instruments which are used in design and configuration of automated systems in electrical, pneumatic domains etc. They typically work for industries with automated processes, such as chemical or manufacturing plants, with the goal of improving system productivity, reliability, safety, optimization and stability.

Instrumentation technologists, technicians and mechanics specialize in troubleshooting and repairing instruments and instrumentation systems. This trade is so intertwined with electricians, pipefitters, power engineers, and engineering companies, that one can find him/herself in extremely diverse working situations. An over-arching term, "Instrument Fitter" is often used to describe people in this field, regardless of any specialization. oo nga.

If we have more I/o's in digital signals than analogue signals normally we choose DCS....and vice versa.

In closed tank, bottom of the tank is connected to the high pressure side of the transmitter. Top of tank is connected to the lower pressure side of the transmitter. In this way vessel pressure can be measured.

In open tank the lower pressure side is vented to the atmosphere. All pressure is applied to the high pressure side. This vessel pressure is measured through high pressure side.

The variation in level of buoyancy resulting from a change in liquid level varies the net weight of the displacer increasing or decreasing the load on the torque arm. This change is directly proportional to change in level and specific gravity of the liquid. The resulting torque tube movement varies the angular motion of the rotor in RVDT providing a rotor change proportional to the rotor displacement, which is converted and amplified to a D.C. current.

Enraf level gauge is based on the ser powered null balance technique. A displacer serves as continuous level sensing element. A two phase ser motor controlled by a capacitive balance system winds unwinds the the measuring wire until the tension in the weight springs is in balance with the weight of the displaced part immersed in the liquid. The sensing system in balance measures the two capacitance formed by the moving central sensing rod provided by the two capacitor plates and the si plates.

The constant voltage circuit consists of a rectifier, CR and a filter capacitor. It is followed by two stages of zener regulation. Abridge configuration is provided to lamp line voltage zener regulation. Regulation 1 and regulation 2 provides relatively provide constant current. Resistors form a bridge that may remoment line voltage effects.

Burnout provides the warnsug feature of driving indicator at the end of scale, if the input circuit is open. A burnout resistor is provided which develops a voltage drop between the measuring circuit and amplifier. The polarity of the signal determines the direction of the servo drive upon an open circuit in the input.

Upscale burnout: R value 10 M

Downscale burnout: R value 22 M

In numerous applications, it is neither desirable nor practical to expose a temperature sensor directly to a material. Wells are therefore used to protect against damage corresion, arosion, aborsion and high pressure processes. A thermo well is also useful in protecting a sensor from physical damage during handling and normal operations.

Materials used in thermo wells: Stainless steel, Inconel, Monel, Alloy Steel, Hastelloy

Different orifice plates are:

1. Concentric

2. Segmental

3. Eccentric

- Concentric: These plates are used for ideal liquid as well as gases and steam service. Concentric holes are present in these plates, thats why it is known as concentric orifice.

- Segmental: This plate has hole in the form of segment of the circle. This plate is used for colloidal and sherry flow measurement.

- Eccentric: This plate has the eccentric holes. This plate is used in viscous and sherry flow measurement.

An orifice tab is welded on the orifice plate which extends out of the line giving an indication of the orifice plate.

Following reasons justify for providing orifice tab:

1. Indication of orifice plate in a line

2. The orifice diameter is marked on it.

3. The material of the orifice plate.

4. The tag number of the orifice plate.

5. To mark the inlet of an orifice.